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7.4 Guiding With the DTI-21 Leaky Guider

The guider allows complete freedom from manual guiding during an integration. When the guider is first turned on, the cursors must be activated by pushing the upper right button on the guider control box. Tap the button until the box and cross are both in a dim mode and then they may be moved together with the direction buttons to center the guide box over the slit or fiber. The position of the box may still be adjusted anytime before or while guiding. To observe using the guider, a star is placed in or near the cursor box, the guider software enabled (click on the ``guider'' button in the TC window), and the integration started. The guider is disabled by clicking the ``guider'' button again, but it will be automatically disabled anytime the ``go there'' button is clicked.

A zoom lens is mounted in front of the ISIT TV and may be controlled with the buttons in the console room or at the slit-head panel. The AC power switch on the slit-head panel must be on. The zoom lens is useful for controlling the size of the slit image with respect to the guide box and for achieving a larger field of view. The position of the stellar image on the TV monitor will generally change with zoom value, and the guide box will have to be repositioned.